1. Technical Field
The present invention relates to a correction information calculating device, an image processing apparatus, an image display system, and an image correcting method.
2. Related Art
Generally, as one example of an image display device, a projector is known. Projectors have advantages such as ease of installation and the ability to display a big screen image. The projectors are used for displaying an image on a planar or curved projection surface. In addition, there are cases where projectors are used for displaying one image as the entirety of a plurality of partial images by projecting the partial images from a plurality of projectors. Recently, an image correcting method for correcting the distortion of images on the projection surface or a difference between relative positions of a plurality of partial images is proposed.
In the above-described image correcting method, for example, the following process is performed. First, a measurement pattern including characteristic points is projected from projectors, and the measurement pattern formed on the projection surface is photographed. Then, correction information representing the amount of correction of the positions of pixels is acquired based on the correspondence relationship between the position of a characteristic point on image data representing the measurement pattern and the position of the characteristic point in the photographed image acquired by photographing the measurement pattern. In a case where an image (hereinafter, referred to as a content image) for a viewer is displayed, image data representing the image is corrected based on the above-described correction information, and an image is displayed based on the corrected image data.
In performing the above-described process, it may be difficult to precisely specify the correspondence relationship between the characteristic points projected onto the photographed image and the projected characteristic points depending on the number or the shape of the characteristic points. When the specifying of the correspondence relationship fails, the process needs to be retried, and the process cannot be performed in an extreme case. As a technology for resolving such disadvantages, there is a technology disclosed in PCT International Publication Pamphlet No. 06/025191. In the technology disclosed in PCT International Publication Pamphlet No. 06/025191, the coordinates of several characteristic points are designated by a user, and the coordinates of the remaining characteristic points are estimated based on the coordinates of the several coordinates through interpolation calculation.
In the technology disclosed in PCT International Publication Pamphlet No. 06/025191, since the coordinates of the characteristic points are designated by the user, and an operation for searching for characteristic points as designated targets is the responsibility of the user, there may be the following disadvantages.
In a case where a measurement pattern including a plurality of characteristic points is used, a case where diagrams representing the characteristic points are all the same, or the like, considerable effort and time are necessary for searching for the characteristic points as designated targets, whereby a considerable burden is placed on the user. In addition, the user may easily incorrectly recognize the characteristic points as the designated targets, and there is a concern about a decrease in the degree of robustness of the process.